fuel petcock issues

[nealy212]

ok here it is,, i never had this problem until i took the petcock off so i could paint the tank, it stayed off for about a week,, before, when i would take the tank off i could turn the arrow to the right to prime and no fuel would drain out, like shutting the fuel off,, no matter what setting i put the the knobb on it would still let fuel out. so i took the pet cock apart and it seemed like it was in working order put it back together and it did ok,, now it leaks throught the small hole on the bottom of the petcock..

[Newbie2it]

Might have put the pressure washer, the one thats cupped, in backwards. Either that or you might have made a small tear in one of the seals. Try rechecking the washer and make sure its in correctly. If it is, then your going to be looking for a rebuild kit or for a new petcock on Ebay. Or someone on here might have one to sell.

BTW, a proper funtioning petcock, will let fuel pass in the prime only position with no vaccum applied to the nipple in the rear of the petcock.

One question, you state "now it leaks throught the small hole on the bottom of the petcock" Are you refering to the nipple in the back of the petcock that the vac line hooks to? Got a picture of the hole we are refering to?

[nealy212]

well if it will let fuel pass in any position how do you get take all the hoses off without spillling fuel everywhere..... well maybe its working right now and was messed up before haha... i will take a pic tomaro and show you,, its on the bottom of the pet cock,, a small hole like pencel lead small

[overboost07]

it shouldnt let fuel pass through unless its on prime if its on or reserve it shouldnt leak, those settings have to have vacuum to let fuel pass

[Newbie2it]

well if it will let fuel pass in any position how do you get take all the hoses off without spillling fuel everywhere..... well maybe its working right now and was messed up before haha... i will take a pic tomaro and show you,, its on the bottom of the pet cock,, a small hole like pencel lead small

Res(erve) and "On" positions on the Katana petcock require vacuum to open the internal valve. Its why theres the nipple thats opposite the knob, to which a vac hose, that comes from the 4th carb attaches to. The carb applies vacuum to the internal valve which opens and allows fuel to flow. Without the vacuum, it will be closed and stop off the flow of gas. Pri(me) however bypasses this part of the internal valve and is specifically intended to allow fuel to flow freely regardless of vacuum.

It sounds like it was messed up before since you said it wouldn't let fuel flow on Pri(me) but now its really messed up since its now leaking from someplace else when it shouldn't be leaking at all.

[91' can of tuna 750]

I had fuel issues one time just replaced the lines and made sure i used small hose clamps on the hoses and made sure to connect the vacuum hose on the back of the pet cock. When I took it off initally I used an air hose and blew it out on every position. There is this place in Phoenix, AZ that sells petcocks for like $20 but you have to bring them you old one so they can pick it from a pile....i love that place its called bob's used motorcycle parts cheap and fair.

[nealy212]

damn well this sucks,,,,guess ima need to see what i can find then

[Kreylyn]

The leak is coming from the diaphram for the vacuum, it has a hole in it. There is a white plastic piece the diaphram gaskes sit on either side of.. the one closer to the fuel side has a hole, and is now letting gas inside when it should not.

The hole in the white plastic piece you see from the outside, is there to allow any build up of gas to evaporate/drain so that petock diaphram will work normally. If it's actually leaking, it is a problem with the diaphram.

The rebuild kit will fix that.

Krey